Acrylic acid can be produced by catalytic vapor-phase oxidation of propane, propylene, acrolein, or the like and obtained by a method for collecting acrylic acid from a gas comprising acrylic acid using a collection solvent.
The conventional methods for the collection of acrylic acid using a solvent from a gas comprising acrylic acid include a method for collecting using water or an aqueous solution as a collection solvent.
In such a collection of acrylic acid using the aqueous solution from the gas comprising acrylic acid, a problem has occurred in that part of acrylic acid is entrained in the moisture contained in the gas discharged from a collection device instead of being collected, and then discharged together therewith.
To solve the problem, studies have been conducted on shape and arrangement of materials in a collection device, the composition of an aqueous solution used for the collection, and so on (e.g., JP 13-19655 A and JP 09-157213 A). However, acrylic acid distilled from the top of the collection column is influenced by operation conditions, so that it is difficult to suppress the loss of acrylic acid from the top of the column stably over long periods. Moreover, the method for employing high-performance packing as materials in the collection device is not a satisfactory method because there is a problem in that clogging tends to occur owing to the polymerization of acrylic acid when acrylic acid is distilled toward the top of the column in an increased amount along with variations in the operation.